examples/pipeline/conn.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2020 Intel Corporation
   3  */
   4
   5 #include <string.h>
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <sys/types.h>
  10
  11 #include <sys/socket.h>
  12
  13 #include <sys/epoll.h>
  14 #include <netinet/in.h>
  15 #include <arpa/inet.h>
  16 #include <errno.h>
  17
  18 #include "conn.h"
  19
  20 #define MSG_CMD_TOO_LONG "Command too long."
  21
  22 struct conn {
  23         char *welcome;
  24         char *prompt;
  25         char *buf;
  26         char *msg_in;
  27         char *msg_out;
  28         size_t buf_size;
  29         size_t msg_in_len_max;
  30         size_t msg_out_len_max;
  31         size_t msg_in_len;
  32         int fd_server;
  33         int fd_client_group;
  34         conn_msg_handle_t msg_handle;
  35         void *msg_handle_arg;
  36 };
  37
  38 struct conn *
  39 conn_init(struct conn_params *p)
  40 {
  41         struct sockaddr_in server_address;
  42         struct conn *conn;
  43         int fd_server, fd_client_group, status;
  44
  45         memset(&server_address, 0, sizeof(server_address));
  46
  47         /* Check input arguments */
  48         if ((p == NULL) ||
  49                 (p->welcome == NULL) ||
  50                 (p->prompt == NULL) ||
  51                 (p->addr == NULL) ||
  52                 (p->buf_size == 0) ||
  53                 (p->msg_in_len_max == 0) ||
  54                 (p->msg_out_len_max == 0) ||
  55                 (p->msg_handle == NULL))
  56                 return NULL;
  57
  58         status = inet_aton(p->addr, &server_address.sin_addr);
  59         if (status == 0)
  60                 return NULL;
  61
  62         /* Memory allocation */
  63         conn = calloc(1, sizeof(struct conn));
  64         if (conn == NULL)
  65                 return NULL;
  66
  67         conn->welcome = calloc(1, CONN_WELCOME_LEN_MAX + 1);
  68         conn->prompt = calloc(1, CONN_PROMPT_LEN_MAX + 1);
  69         conn->buf = calloc(1, p->buf_size);
  70         conn->msg_in = calloc(1, p->msg_in_len_max + 1);
  71         conn->msg_out = calloc(1, p->msg_out_len_max + 1);
  72
  73         if ((conn->welcome == NULL) ||
  74                 (conn->prompt == NULL) ||
  75                 (conn->buf == NULL) ||
  76                 (conn->msg_in == NULL) ||
  77                 (conn->msg_out == NULL)) {
  78                 conn_free(conn);
  79                 return NULL;
  80         }
  81
  82         /* Server socket */
  83         server_address.sin_family = AF_INET;
  84         server_address.sin_port = htons(p->port);
  85
  86         fd_server = socket(AF_INET,
  87                 SOCK_STREAM | SOCK_NONBLOCK,
  88                 0);
  89         if (fd_server == -1) {
  90                 conn_free(conn);
  91                 return NULL;
  92         }
  93
  94         status = bind(fd_server,
  95                 (struct sockaddr *) &server_address,
  96                 sizeof(server_address));
  97         if (status == -1) {
  98                 conn_free(conn);
  99                 close(fd_server);
 100                 return NULL;
 101         }
 102
 103         status = listen(fd_server, 16);
 104         if (status == -1) {
 105                 conn_free(conn);
 106                 close(fd_server);
 107                 return NULL;
 108         }
 109
 110         /* Client group */
 111         fd_client_group = epoll_create(1);
 112         if (fd_client_group == -1) {
 113                 conn_free(conn);
 114                 close(fd_server);
 115                 return NULL;
 116         }
 117
 118         /* Fill in */
 119         strncpy(conn->welcome, p->welcome, CONN_WELCOME_LEN_MAX);
 120         strncpy(conn->prompt, p->prompt, CONN_PROMPT_LEN_MAX);
 121         conn->buf_size = p->buf_size;
 122         conn->msg_in_len_max = p->msg_in_len_max;
 123         conn->msg_out_len_max = p->msg_out_len_max;
 124         conn->msg_in_len = 0;
 125         conn->fd_server = fd_server;
 126         conn->fd_client_group = fd_client_group;
 127         conn->msg_handle = p->msg_handle;
 128         conn->msg_handle_arg = p->msg_handle_arg;
 129
 130         return conn;
 131 }
 132
 133 void
 134 conn_free(struct conn *conn)
 135 {
 136         if (conn == NULL)
 137                 return;
 138
 139         if (conn->fd_client_group)
 140                 close(conn->fd_client_group);
 141
 142         if (conn->fd_server)
 143                 close(conn->fd_server);
 144
 145         free(conn->msg_out);
 146         free(conn->msg_in);
 147         free(conn->prompt);
 148         free(conn->welcome);
 149         free(conn);
 150 }
 151
 152 int
 153 conn_poll_for_conn(struct conn *conn)
 154 {
 155         struct sockaddr_in client_address;
 156         struct epoll_event event;
 157         socklen_t client_address_length;
 158         int fd_client, status;
 159
 160         /* Check input arguments */
 161         if (conn == NULL)
 162                 return -1;
 163
 164         /* Server socket */
 165         client_address_length = sizeof(client_address);
 166         fd_client = accept4(conn->fd_server,
 167                 (struct sockaddr *) &client_address,
 168                 &client_address_length,
 169                 SOCK_NONBLOCK);
 170         if (fd_client == -1) {
 171                 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 172                         return 0;
 173
 174                 return -1;
 175         }
 176
 177         /* Client group */
 178         event.events = EPOLLIN | EPOLLRDHUP | EPOLLHUP;
 179         event.data.fd = fd_client;
 180
 181         status = epoll_ctl(conn->fd_client_group,
 182                 EPOLL_CTL_ADD,
 183                 fd_client,
 184                 &event);
 185         if (status == -1) {
 186                 close(fd_client);
 187                 return -1;
 188         }
 189
 190         /* Client */
 191         status = write(fd_client,
 192                 conn->welcome,
 193                 strlen(conn->welcome));
 194         if (status == -1) {
 195                 close(fd_client);
 196                 return -1;
 197         }
 198
 199         status = write(fd_client,
 200                 conn->prompt,
 201                 strlen(conn->prompt));
 202         if (status == -1) {
 203                 close(fd_client);
 204                 return -1;
 205         }
 206
 207         return 0;
 208 }
 209
 210 static int
 211 data_event_handle(struct conn *conn,
 212         int fd_client)
 213 {
 214         ssize_t len, i, status;
 215
 216         /* Read input message */
 217
 218         len = read(fd_client,
 219                 conn->buf,
 220                 conn->buf_size);
 221         if (len == -1) {
 222                 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
 223                         return 0;
 224
 225                 return -1;
 226         }
 227         if (len == 0)
 228                 return 0;
 229
 230         /* Handle input messages */
 231         for (i = 0; i < len; i++) {
 232                 if (conn->buf[i] == '\n') {
 233                         size_t n;
 234
 235                         conn->msg_in[conn->msg_in_len] = 0;
 236                         conn->msg_out[0] = 0;
 237
 238                         conn->msg_handle(conn->msg_in,
 239                                 conn->msg_out,
 240                                 conn->msg_out_len_max,
 241                                 conn->msg_handle_arg);
 242
 243                         n = strlen(conn->msg_out);
 244                         if (n) {
 245                                 status = write(fd_client,
 246                                         conn->msg_out,
 247                                         n);
 248                                 if (status == -1)
 249                                         return status;
 250                         }
 251
 252                         conn->msg_in_len = 0;
 253                 } else if (conn->msg_in_len < conn->msg_in_len_max) {
 254                         conn->msg_in[conn->msg_in_len] = conn->buf[i];
 255                         conn->msg_in_len++;
 256                 } else {
 257                         status = write(fd_client,
 258                                 MSG_CMD_TOO_LONG,
 259                                 strlen(MSG_CMD_TOO_LONG));
 260                         if (status == -1)
 261                                 return status;
 262
 263                         conn->msg_in_len = 0;
 264                 }
 265         }
 266
 267         /* Write prompt */
 268         status = write(fd_client,
 269                 conn->prompt,
 270                 strlen(conn->prompt));
 271         if (status == -1)
 272                 return status;
 273
 274         return 0;
 275 }
 276
 277 static int
 278 control_event_handle(struct conn *conn,
 279         int fd_client)
 280 {
 281         int status;
 282
 283         status = epoll_ctl(conn->fd_client_group,
 284                 EPOLL_CTL_DEL,
 285                 fd_client,
 286                 NULL);
 287         if (status == -1)
 288                 return -1;
 289
 290         status = close(fd_client);
 291         if (status == -1)
 292                 return -1;
 293
 294         return 0;
 295 }
 296
 297 int
 298 conn_poll_for_msg(struct conn *conn)
 299 {
 300         struct epoll_event event;
 301         int fd_client, status, status_data = 0, status_control = 0;
 302
 303         /* Check input arguments */
 304         if (conn == NULL)
 305                 return -1;
 306
 307         /* Client group */
 308         status = epoll_wait(conn->fd_client_group,
 309                 &event,
 310                 1,
 311                 0);
 312         if (status == -1)
 313                 return -1;
 314         if (status == 0)
 315                 return 0;
 316
 317         fd_client = event.data.fd;
 318
 319         /* Data available */
 320         if (event.events & EPOLLIN)
 321                 status_data = data_event_handle(conn, fd_client);
 322
 323         /* Control events */
 324         if (event.events & (EPOLLRDHUP | EPOLLERR | EPOLLHUP))
 325                 status_control = control_event_handle(conn, fd_client);
 326
 327         if (status_data || status_control)
 328                 return -1;
 329
 330         return 0;
 331 }